The subject matter of the present invention pertains to means for converting an electrical signal defining a refreshed raster-scan image into a permanent hard-copy representation of such image.
Known examples of such systems include those disclosed by Japanese patent publication No. 47562/74, Gibson U.S. Pat. No. 3,679,824, and Unger et al U.S. Pat. No. 3,811,007, the latter two of which are assigned to the assignee of the present invention. In each of the identified systems, successive portions or slices of an image to be copied are displayed on a display screen and then moved across the screen at a speed synchronous with the movement of a recording medium disposed adjacent the screen. In this manner, an image larger than the screen itself can be scrolled across the screen so as to produce in the similarly scrolled recording medium a reconstructed representation of the entire image. A common disadvantage of such systems is their inability to produce color copies of color images.
Other prior art systems of some pertinency include those disclosed by U.S. Pat. Nos. 3,716,664; 3,685,899; 3,006,260; 2,878,309; 2,600,868; and 2,531,031. Typical of these systems is that of U.S. Pat. No. 3,685,899 wherein a special form of field sequential video color is recorded on standard black and white film as a black and white separation master using a continuous film motion electronic beam recorder, and then a standard color film is made from the separation master by exposing each frame of the film in sequence to red, green, and blue separation images using appropriate color filters. A disadvantage of such a field sequential color system is its requirement for special lenses, color wheels, or three-gun continuous film motion recorders, each of which adds to the size and cost of the resultant system.
A further example of a motion picture printer is that disclosed in Horsley U.S. Pat. No. 3,005,042 wherein three electrical signals representing the three primary colors of an image appearing on a first color film are converted via three single-color cathode-ray tubes into a composite image fragment for presentation to a second color film. With both films scrolled past their respective input and output stations at the same speed, the image information from the first film can be effectively transferred to the second. A principal disadvantage of the Horsley system is its requirement for three separate cathode-ray tubes to produce the composite image fragment. Although Horsley indicates that a conventional shadow mask type tricolor cathode-ray tube, using three electron guns, could be employed in place of the three separate tubes, such a single tube would not provide the same degree of resolution in the image produced or permit the same flexibility of color balance or other incidental adjustments.